Lock for sewing-machine stitch regulators



April 19, 1949. M, lNGWER 2,467,672

LOCK FOR SEWING MACHINE STITCH REGULATORS Filed Feb. 4, 1947 /VAX Aven/5f? IN VEN TGR.

3*, my. fff

Patented Apr. 19, 1949 LOCK FOR SEWING-MACHINE STITCH REGULATORS Max Ingwer, New York, N. Y., assignor to Consolidated Sewing Machine & Supply Co., Inc., New York, N. Y., a corporation of New York Application February 4, 1947, Serial No. 726,393

4 Claims.

The invention disclosed in this patent application relates to lock mechanism for protecting and preventing unauthorized adjustment of the stitch regulators of sewing machines.

Specifically it is a purpose of the invention to provide a lock for asewing machine of the type in which length of the stitch is varied by pressing a push button in the head of the machine and then turning the handwheel to effect a shifting of the feed eccentric on the arm shaft.

Important related objects are to provide such a lock or guard which can be quickly and easily applied to existing machines without requiring any additional fastenings or other parts and which while fully strong and reliable will be small in size so as not to project or add objectionably to the bulk of the machine.

Along this same line it is a purpose of the invention to provide a lock structure which will merge into the outline of the sewing machine head so as not to detract from the smooth and ornamental appearance of the head.

Other desirable objects and the novel features through which the purposes of the invention are attained are set forth or will appear in the course of the following specification.

The drawing accompanying and forming part of the specification illustrates a present commercial embodiment of the invention. Structure, however, may be modied and changed as regards the immediate illustration, all within the true intent and broad scope of the invention as hereinafter defined and claimed.

Figure 1 in the drawing is a broken part sectional front view of a sewing machine head having the invention applied thereto, the cover constituting the lock structure appearing in section.

Figure 2 is a plan view of the cover in locking position over the cap or escutcheon plate carrying the stitch regulator push button.

Figure 3 is a plan View showing these parts as they appear with the cover unlocked and removed.

Figure 4 is an enlarged broken sectional View as on substantially the plane of line 4--4 of Figure 2.

Figure 5 is an inside view of the guard cover.

Figure 6 is an enlarged broken sectional detail on substantially the plane of line 6 6 of Figure 1.

Figure 7 is a plan view of the lock mounting frame.

In Figures 1 and 4 a sewing machine head of the type above referred to is shown at 1, with stitch regulating mechanism in the form of a push button 8 engageable in a notch 9 in the slide IIJ which locks the feed eccentric II to the shaft I2.

The arm shaft I2 may be turned by handwheel I3 to nd the position where the point of the push button 8 will enter the notch 9 and then a further movement of the push button will press the slide Ill downward to release the feed eccentric from the shaft, whereupon the shaft may then be turned one way or another while the push button is held in to vary the angular relation of the eccentric on the shaft and hence the number of stitches per inch that will be produced, such adjustment being usually facilitated by a stitch indicator scale on the inside face of the handwheel.

The locking of this stitch regulator is accomplis-hed in the present invention by means of a guard or cover which can be ylocked in position over the push button.

This cover is designated I4 and is shown as a narrow elongated convexly curved structure eX- tending completely over the push button cap, cover plate or escutcheon l5, from one end to the other. The securing of this protective guard or cover is effected in the illustration by a base plate or flange i6 fastened to the head by means of the escutcheon and carrying at its opposite ends, means for attachment of the cover thereto.

Specifically, the securing flange I6 is shown as a flat washer like ele-ment conforming at the outside to the shape of the boss or "pad" I'I' about the opening I8 in the top of the head and at the inside to the shape of the dependent flange I9 of the escutcheon which fits down into such opening. This ange or mounting washer also has openings, registering with those in the escutcheon to receive the securing screws 2li which fasten the escutcheon in place.

Consequently, the lock carrying flange I6 may be mounted on the machine upon removing the two screws 2t and then replacing the escutcheon with the flange It interposed between the base of the escutcheon and the pad on which the escutcheon is mounted on the machine. Cork or other such gaskets 2l may be disposed at opposite sides of the interposed mounting Washer I6.

At one end the guard cover I4 is shown having a dependent portion 22 slotted at 23 to pass over a lug 24 projecting from that end of the mounting washer.

At the opposite end the guard cover is shown as carrying a pin tumbler lock 25, operable by a key and having a locking lug or rollback 26 engageable in an opening 27 in the keeper lug 28 bent up at an angle from that end of the mounting plate.

The keeper slot 2l may be slightly inclined so as to accomplish a pulling of the guard cover tightly in place as the key turns the rollback into the locking position.

The use of the lock described does not vary the stitch regulating operations except possibly for a slight additional movement of the push button resulting from the interposition of the mounting plate between the escutcheon and machine head. This plate being fully supported and held all the way around may be quite thin so that this variation is of no consequence.

After securing the mounting plate on the head the cover may be applied by simply engaging the slotted end extension 22 of the same over the lug 2li and then lowering the cover over the opposite end to a position where the rollback lug 26 will enter the slot 27 in the keeper lug 28. Then upon turning the required key in this lock, the locking lug 26 will be carried into engagement with the keeper to positively secure the guard in place and prevent any unauthorized adjustment of or tampering with the stitch regulating mechanism.

The guard cover with the lock incorporated therein is a relatively small structure which shaped as described and illustrated covers the esoutcheon and base plate securing screws as well as the push button, aiording full protection and merging smoothly with the head of the machine, conforming and appearing in general as a basic part of the machine.

The invention, it will be seen, can be produced at low cost, making it practical for use with machines of the type indicated.

Figure 6 shows how the keeper slot 21 may be inclined slightly to cause the dog 26 of the tumbler as it engages with the inclined shoulder of the keeper to draw the guard cover tight and rm down over the escutcheon to avoid vibration or rattling.

What is claimed is:

1. A lock for a sewing machine stitch regulator of the type including a cover plate having a dependent iiange to enter an opening in the top of a sewing machine head, secured by screws over the machine head and carrying a push button for actuation of mechanism within the head, said lock including a iiat mounting washer engaged beneath the base of said cover plate and having an opening receiving the dependent flange held by the same screws which secure the cover plate in place, and whereby said mounting washer is positively positioned and secured on the machine head independently of the stitch regulator adjustment, said mounting washer having a projecting lug at one end and an angularly up-struck slotted keeper lug at the opposite end, projecting beyond the edges of the overstanding cover plate, a guard having a slotted dependent extension at one end engageable over said rst mentioned lug and eX- tending from that end across the cover plate and covering both the securing screws and the push button and a key operated lock within the opposite end portion of the guard and having a locking lug engageable in said slot in the keeper lug, whereby the screws which fasten the cover plate and mounting washer in place cannot be reached when the guard is locked to said mounting washer.

2. A lock for a sewing machine stitch regulator of the type including a push button and a cover plate for mounting the same and having means for securing it on a sewing machine head, said lock comprising a mounting washer disposed between the cover plate and machine head and thereby held by the same means which fasten the cover plate in place, said mounting washer having projections at opposite ends of the same, a guard completely covering the push button and the securing means for the cover plate, said guard having means at one end removably engageable with the projection at one end of the mounting Washer and a key operable lock in the opposite end portion of said guard cooperatively engageable with the projection at said opposite end of the mounting washer.

3. A lock for a sewing machine stitch regulator of the type including a. push button and a cover plate for mounting the same and having means for securing it on a sewing machine head, said lock comprising a mounting washer disposed between the cover plate and machine head and thereby held by the same means which fasten the cover plate in place, said mounting washer having projections at opposite ends of the same, a guard completely covering the push button and the securing means for the cover plate, said guard having means at one end removably engageable with the projection at one end of the mounting washer and a key operable lock in the opposite end portion of said guard cooperatively engageable with the projection at said opposite end of the mounting washer, said latter lug having a keeper shoulder inclined in respect to the axis of the key actuated lock and the latter including a rollback engageable with said inclined shoulder to draw the guard closely down over the top of the cover plate.

4. A lock for a sewing machine stitch regulator of the type including a push button and a cover plate for mounting the same and having means for securing it on a sewing machine head, said lock comprising a mounting washer disposed between the cover plate and machine head and thereby held by the same means which fasten the cover plate in place, said mounting washer having projections at opposite ends of the same, a guard completely covering the push button and the securing means for the cover plate, said guard having means at one end removably engageable with the projection at one end of the mounting washer and a key operable lock in the opposite end portion of said guard cooperatively engageable with the projection at said opposite end of the mounting Washer, the latter lug being angularly extended in respect to the mounting washer and having a transverse slot therein and the key operated lock being mounted in the top of the guard and including a rollback positioned to rotate into said slot.

MAX INGWER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,181,828 Ingwer et al Nov. 28, 1939 2,282,047 Graesser May 5, 1942 

